Latching mechanism



Aug. 6, 1929. I J. R. McFARLlN LATCHING'MEGHANISM Filed Nov. 10, 1924 J a i of w m W 7, m

Patented Aug. 6, 1929.

UNITED STATES PATENT OFFICE.

JOHN ROBERT MCFARLIN, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO ELEC- TRIO SERVICE SUPPLIES COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A COR- PORATION OF PENNSYLVANIA.

LATGHING MECHANISM.

Application filed November 10, 1924. Serial No. 748,890.

My invention is primarily intended for use in conjunction with the blades of electric switches, particularly of the type known as disconnecting switches, to prevent the fortuitous opening of such switches sometimes resulting from accidental contact, the force of gravity, or the magnetic effect of unduly heavy currents passing therethrough. My improved mechanism is, however, applicable for use in connection with othermembers, one of which is movable relatively to the other where it is important that the latching mechanism hold fast against disengagement by pressure on the movable member but be disengaged and the movable member actuated by a single operation.

In accordance with my invention, I provide latching mechanism movable transversely to the plane of movement of the switch blade or other movable member and preferably so mounted that pressure against the blade tends I to force the latching means into tighter engagement. The latching mechanism is automatically operated to secure the blade by closing the switch, and the blade or movable member has connected therewith an actuator for disengaging the latching mechanism, the actuator being preferably so mounted on the blade as to be operable by a force acting in substantially the same direction as the force required for moving the blade from its seat.

In practice, the blade of a disconnecting switch is usually pivotally mounted on one contact member and wipesanother or other contact members, and in the application of my improvements to such construction I preferably pivot a latching pawl on eachside of the blade and on axes transverse to the axis of the blade. -A rocking actuator, movable about an axis parallel with the axis of the blade, may be rocked by a thruster pull thereon in the direction requiredfor opening the switch and releases the pawls from a keeper. Continuation of the thrust or pull on them:- tuator moves the blade from its seat.

In closing the switch, the latching mechanism automatically engages the keeper when the blade reaches its normally closed positionand the blade is securely held until the actuator is again operated.

The characteristic features and advantages of my improvements will more fully appear from the following description and the accompanying drawings of a preferred embodiment of my invention.

In the drawings, Fig. 1 is a side elevation of myimproved latching means applied to an electrical switch; Fig. 2 is an end view of the same broken along the line 9r2 of Fig. 1; F 3 is a top plan view of my latching mechanism on the end of a switch blade as shown in Fig. 1; and Fig. 4 is an end view, partly in section, showing the mechanism with the latches retracted.

As illustrated in the drawings, my improved latching mechanism is applied to a disconnecting switch comprising a channeled base 1 having seated therein the supports 2 and 2 on which are fixed insulators 3 and 3. The insulators are surmounted by caps 4, 4, on which are secured conducting blocks 5, 5. Terminals 6, 6 for the electric conductors .7, 7 are boltedto the blocks 5, 5, and webs 8, 8 are sweated into slots 9, 9 in the blocks 5, 5 to form jaws or wipes for the switch blade 10. The switch blade 10 may be pivoted in the clevis formed by the members 8 by a bolt 11 passing therethrough and having on the endsthereof spring washers 12 for yieldingly drawing the legs of the clevis t0- gethcr and maintaining good electrical contact between them and the blade 10. A screw or bolt 13 may be employed to adjust the spread of the webs 8 so as to permit movement of the blade 10 between such webs whlle securing good electrical contact between the webs and blade.

-The block 5 has bolted thereto a yoke shaped housing 14 having flanges 15 forming channels '16 on opposite sides of the plane of movement of the blade 10, and pawls 17 are pivot-ally connected with the flanges 15 on axes transverse to the axis of oscillation of the blade lOby pintles 18. The pawls are normally pressed toward one another by springs 19 wound. around pins 20 fixed in the flanges 15, the springs having their tails 21 engaging the slotted faces 22 of the pawls. The throw of the pawls by the springs is limited by the shoulders 23 at the tops of the pawls which engage the web of the yoke 14; when the pawls are rocked to the desired limits.

The blade section movable between the pawls 17 carries a keeper preferably c0mprising a channeled block pinned and sweated to the bottom of the blade and having beveled shoulders or uppersurfaces 25 so inclined that the lower ends of the dogs 17 when in contact with them may slide over them with a small angular clearance. When a dog 1'? is thrown by the spring 19 to its extreme position the bevel of the adjacent shoulder 25 is tangent to the surface of the nose 23 of the dog at a point below a line passing through the center of the nose and the center of the pin 18, ,so that pressure of the shoulder against the nose forces the dog toward the blade.

A bifurcated actuator 26 is fulcrumed on the blade 10 by a bolt 27 and is provided with an end loop 28 for the engagement of a hook.

A stud 29 set in the blade 10 is engaged in the arcuate slots 80 in the furcations 31 of the actuator to limit the movements thereof. Each furcation 31 is provided with a double bevelled edge 32, and the over all width of the furcations is slightly greater than the over all width of the protuberant block 2e.

WVhen a blade 10 is thrown to close a circuit between the terminals 6 and 6,th'e bottom of the keeper 24 engages the upper inclined surfaces of the dogs 17, which are forced back into the channels 16 against the action of the springs 19. As soon as the block 2 L has passed the dogs, the latter are rocked by the springs 19 so that their noses 23 are ejected from the channels 16 into the plane of movement of the keeper 2%. If force be now applied to the blade to open the switch, the shoulders 25 engage-the noses 23 of the dogs at points below the center lines thereof so that the resultant force tends to press the dogs upwardly or toward one another, and this pressure is resisted by the engagement of the shoulders 23 with the housing 14. Even should such resistance fail, the switch could not be opened, since the dogs would engage the blade 10 and the distance between the pivots 18 is less than the sum of the distances between the axes of rotation of the dogs and their noses, plus the thickness of the switch blade.

\Vhen, however, it is desired to open the switch, this may be readily effected by engaging the hooked end of a pole in the loop -28and drawing or thrusting outwardly from the base 1, thereby turning the rocker 26 on its fulcrum 27 and pressing the outer beveled edges 32 of the furcations 31 against the inclined surfaces of the dogs 17, which are thereby forced back into the channels 16 beyond the edges of the keeper 24, the movement of the actuator 26 bein limited by the engagement of the inner beveled edges 32 against the shoulders 25. Continuance of the pressure on the ring 28 rocks the blade on its pivot and opens the switch.

It will be obvious that certain of the advantages of my improvements may be secured by the use of latching and releasing mechanisms on but one side of the switch blade and that the connections of the keeper and latching devices with the movable memher and block may be transposed.

Having described my invention, I claim:

1. The combination with a plurality of members one of which is movable relatively to the other, of means comprising a latch fulcrumed on one of said members and normally inclined toward the other of said members, the latter member normally lying in a plane between the fulcrum point of said latch and the base of the member on which the latch is mounted; the member toward which the latch is inclined engaging and rocking said latch upon the movement of the movable member in one direction, and means for rock; ing said latch to prevent such engagement thereof.

2. The combination with a plurality of members one of which is movable about an axis, of mechanism comprising a latch normally inclined toward said movable member movable about an axis transverse to the axis of said member and a-rigid stop limiting the rotation of such latch spaced laterally from the plane of said movable member.

3. The combination with a plurality of members. one of which is movable relatively to the other, of mechanism comprising a latch fulcrumed on one of said members ata point spaced laterally from the plane of the other member and movable transversely to the plane of movement of the movable member and toward such plane by pressure on the latch by the movable member, and means for retracting said latch and operating said movable member.

4. The combination with a plurality of members one of which is movable relatively to the other, of a rigid catch pivotally connected with one of said members for engaging the other member said catch being fulcrumed at a point further removed from the base of its supporting member than is point of the other member engaged by such catch, and an actuator movable about an axis transverse to the axis of the catch for operating said catch.

5. Thecombination with a plurality of members one of which is movable relatively to the other, of a plurality of movable catches mounted upon bearings of one of said members and beyond the plane of the other, said catches normally converging toward said last named member and being movable into engagement with opposite sides thereof by pressure thereof on such'catches.

6. The combination with a plurality of members one of which is movable relatively to the other, of a plurality of movable catches projecting toward the direction of movement of said movable member when moving toward the other member, and a device carried by and having a limited movement relatively to and oppositely to the direction of movement of said movable member for operating said catches.

7. The combination with a plurality of members one of which is movable relatively to the other and one of which forms a yoke for housing the other, of a pair of catches mounted adjacent to the free ends of said yoke and movable downwardly between the legs thereof, said catches normally preventing the removal of the housed member from the housing. a

8. The combination of a housing forming a channel, a pawl movable in said channel, a spring for operating said pawl, a member having a part engaged by said pawl and tending to move it further into the path of said member and an actuator carried by said member for operating said pawl.

9. The combination with a movable blade, of a plurality of supports on opposite sides of the plane of movement of said blade, pawls pivotally connected with said supports and movable about axes extending in the direction of the length of the closed blade into and out of the plane of movement of said blade, and a member carried by said blade for rocking said pawls.

10. The combination with a yoke member having channels in the legs thereof, pawls movable in said channels, and springs for actuating said pawls, of a member having a keeper eoacting with said pawls, one of said members being movable relatively to the other, and an actuator carried by said movable member for actuating said pawls in the direction of the closing movement of said movable member.

11. The combination with a pivoted blade, of latching means therefor comprising catches movable on axes transverse to the axis of said blade, springs for operating said catches in the direction of the opening movement of said blade, and a rocker movable about an axis parallel zith the aXisof said blade for operating said catches, said rocker being movable between the axes of said catches. a

12. The combination with a blade having a keeper with an inclined surface, of a pivoted pawl adapted for cooperation with said surface to latch said blade.

13. The combination with a blade having a keeper with inclined surfaces converging toward said blade, of pawls for engaging said surfaces.

14. he combination with a blade having a keeper with inclined surfaces converging toward said blade, of pawls movable into the plane of said surfaces and movable by said keeper toward said blade.

15. The combination with a switch blade having thereon a keeper with inclined sur- 

